This report contains summaries of 720 recent and current experiments in elementary particle physics (experiments that finished taking data before 1980 are excluded). Included are experiments at Brookhaven, CERN, CESR, DESY, Fermilab, Moscow Institute of Theoretical and Experimental Physics, Tokyo Institute of Nuclear Studies, KEK, LAMPF, Leningrad Nuclear Physics Institute, Saclay, Serpukhov, SIN, SLAC, and TRIUMF, and also experiments on proton decay. Instructions are given for searching online the computer database (maintained under the SLAC/SPIRES system) that contains the summaries. Properties of the fixed-target beams at most of the laboratories are summarized.

An approximately Coulomb-corrected, charge-symmetric R-matrix prediction for n${\mathrm{\ensuremath{-}}}^{3}$H scattering from analyzing p${\mathrm{\ensuremath{-}}}^{3}$He data is described, which deviates at most by 2% from the n${\mathrm{\ensuremath{-}}}^{3}$H total cross section. The total cross section, together with a new measurement of the coherent scattering length now allows two possible sets of singlet and triplet scattering lengths ${\mathit{a}}_{\mathit{s}}$ and ${\mathit{a}}_{\mathit{t}}$. Our analysis agrees well with the new value of the coherent scattering length, and determines the set with ${\mathit{a}}_{\mathit{s}}$/${\mathit{a}}_{\mathit{t}}$>1 to be the correct one.

Modern treatments of energy loss in plasmas through elastic scattering of energetic ions require complete knowledge of charged-particle elastic cross sections. R-matrix theory provides an explicit separation of nuclear and Coulomb effects in these cross sections, and gives reasonable extrapolations to small angles and low energies, where data may be scarce. We outline the calculation of charged-particle elastic cross sections from R-matrix parameters, and give examples for d-T, d-α, and t-α scattering, obtained from comprehensive analyses of reactions in the 5He, 6Li, and 7Li compound systems. Expansion coefficients for an exact polynomial representation for the difference of the scattering and Rutherford cross sections (σNI) are given for d-T scattering. Integral quantities involving σNI calculated from the present cross sections disagree substantially in some cases near resonances with a recent Livermore evaluation.

Without Abstract

Accurate measurements of $p\ensuremath{-}\ensuremath{\alpha}$ elastic scattering cross sections were made at energies of 11.157, 12.040, 13.600, and 14.230 MeV. The average relative error is about 0.6% and the scale error is 0.37%. These data and all available cross section and spin-dependent measurements of $p\ensuremath{-}\ensuremath{\alpha}$ scattering between 0 and 18 MeV were collected and prepared for input to a general purpose $R$-matrix analysis program. Strict statistical criteria were used for the elimination of data. The resulting search on 1131 data produced a unique fit with a ${\ensuremath{\chi}}^{2}$ per degree of freedom of 1.001 which is within one standard deviation in ${\ensuremath{\chi}}^{2}$ space. Arbitrary normalizations to the data were not allowed; a normalization was treated as another datum restrained by a scale error obtained from the experimental information. The parameter space was made up of background contributions in $S$, $P$, $D$, and $F$ states with an additional level each in the ${P}_{\frac{3}{2}}$ and ${P}_{\frac{1}{2}}$ states. There were 14 free parameters. For the first time, the reduced widths of the $p$-wave resonance states come out almost equal. Comparisons are made to the $R$-matrix analysis of Stammbach and Walter and to the phase shift analysis of Arndt, Roper, and Shotwell.NUCLEAR REACTIONS $^{4}\mathrm{He}(p, p)$, $E=11\ensuremath{-}14$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$, $\ensuremath{\theta}(\mathrm{c}.\mathrm{m}.)=19\ensuremath{-}167\ifmmode^\circ\else\textdegree\fi{}$, $\ensuremath{\Delta}\ensuremath{\theta}=0.03\ifmmode^\circ\else\textdegree\fi{}$, $\ensuremath{\Delta}\ensuremath{\sigma}=0.06%$; calculated $R$-matrix parameters for all $^{4}\mathrm{He}(p, p)^{4}\mathrm{He}$ data, $E=0\ensuremath{-}17$ MeV.

Experiments involving polarization techniques have nowhere unearthed a richer structure of observed phenomena than in those scattering and reaction processes involving very few nucleons. This paper is concerned with a program, carried out with colleagues at Los Alamos, with its first goal as a phenomenological understanding of these processes. It is the belief of those of us working on this program that our approach is essentially dictated by the fact that the overwhelming amount of information already collected seems to be still only marginally sufficient to describe the complex behavior of these systems. This somewhat paradoxical situation, that an almost unmanageable quantity of data is still perhaps just on the threshold of encompassing all aspects of the behavior of such a system, seems to call for an approach with two main features. First, all channels and all complementary experiments should be described simultaneously. Second, an energy dependent parameterization should be used, if only because the data are not sufficiently complete at single energies. The simultaneous description of all channels allows us to make use of the very important principle of unitarity of the collision matrix S. The need for an energy dependent parameterization has led us to choose the R-matrix formalism. In this context that formalism is to be regarded as a practical tool. This paper does not discuss the role of the R-matrix in general theories of nuclear reactions. It may be, however, that the results of the present work will have a place in such discussions.

been subjected to a phase shift analysis. Up to 45 MeV a single, continuous solution could be determined using phase shifts up through G-waves. As in an earlier phase shift analysis the phase shifts exhibit a smooth variation with energy except for the well-known resonance region around 23.4 MeV. Above 45 MeV some improvement was obtained with the inclusion of a small H-wave contribution. New total reaction cross section data were employed as a constraint on the imaginary parts of the phase shifts. The new analsis corroborates an early finding that the inelasticity is mainly associated with the even partial waves.